Fish and chips are one of Britain's favourite takeaways and Friday is still the most popular day for eating this hot and nutritious national dish with its firm flakes of white fish in crisp golden batter.

But for the growing number of those with Coeliac disease or gluten intolerance, a portion of fried fish from the local chippy is off the menu because of the wheat flour and baking powder used to make the batter.

Responding to this, a number of fish and chip shops and restaurants offer the option of ordering the meal gluten-free, which is welcome. But - a word of warning here - it's not enough simply to cook a portion of fish in gluten-free batter.

Gluten, the allergen protein in wheat, cannot be killed with high heat and there is a risk of contamination if chips are cooked in the same oil as battered or breaded products.

Guidelines drawn up by Coeliac UK offer the following tips to fish and chip shop owners:

• Use separate, clean oil to fry chips and gluten-free battered fish. Simply filtering oil is not sufficient.
• Have a dedicated 'gluten-free night' on the day that the chip fryer is cleaned and fresh oil used.
• Use separate tongs to serve chips and gluten-free products to prevent contamination.
• Make sure that the gluten-free batter/mix is clearly labelled.
• Clean mixing equipment before using gluten-free mixes to make sure wheat flour does not contaminate the gluten-free batter.
• Check the labels of tomato ketchup, sauces, baked beans, salad dressings, etc to see if they are suitable.

Coeliac UK encourages restaurant owners and takeaway shops to follow the guidelines and apply for accreditation.

If you see the gf knife & fork sign (left) at your local fish and chip shop it means it has gained approval from Coeliac UK and it's safe to eat there.

And finally, remember that salt and vinegar are gluten-free. Although barley malt vinegar is produced from barley, the processing involved removes barley protein and removes the gluten, making it suitable for people with coeliac disease.

Enjoy!